Radio communication apparatus and subcarrier assignment method

ABSTRACT

Wireless communication apparatus capable of increasing transmission efficiency by selecting data for scheduling according to data type, and capable of achieving low power consumption and high-speed signal processing is disclosed. With this apparatus, a control section ( 108 ) allocates transmission data sequence  1  to subcarriers of superior quality by carrying out scheduling for the transmission data sequence  1  based on CQI sent from communication terminal apparatus and required transmission rate information for each communication terminal apparatus, and allocates transmission data sequence  2  to preassigned subcarriers. Channel allocation section ( 115 ) allocates data for transmission data sequence  1  to subcarriers designated by control section ( 108 ). Channel allocation section ( 116 ) allocates data for transmission data sequence  2  to subcarriers designated by control section ( 108 ).

TECHNICAL FIELD

The present invention relates to a wireless communication apparatus andsubcarrier allocation method, and particularly to a wirelesscommunication apparatus and subcarrier allocation method where data isallocated to a plurality of subcarriers using, for example, OFDM.

BACKGROUND ART

In the related art, multi-carrier transmission such as OFDM and MC-CDMAetc. has been examined as a beyond 3G system taken as a systemfulfilling high-speed packet transmission requirements. It is possibleto improve frequency utilization efficiency in multi-carriertransmission by carrying out adaptive modulation and scheduling everysubcarrier and by allocating data transmitted to each mobile station tosubcarriers of superior reception quality within the communication bandwidth using frequency scheduling. At base station apparatus, in order tocarry out frequency scheduling by allocating data to be transmitted toeach mobile station to subcarriers of superior reception quality, themobile station notifies the base station apparatus of a CQI (ChannelQuality Indicator) constituting individual channel quality informationfor every subcarrier for all subcarriers. The base station apparatusthen determines the subcarrier, modulation scheme and coding rate to beused at each mobile station in accordance with a predeterminedscheduling algorithm taking into consideration the CQI. Technology isdisclosed, for example, in Japanese Patent Laid-open Publication No.2002-252619 where frequency scheduling is carried out using all of thesubcarrier CQI's from all of the users in the event that a base stationtransmits to a plurality of mobile stations at the same time.

Specifically, based on the CQI, the base station apparatus allocates alarge number of subcarriers to each user in an appropriate manner(frequency division multiplexing) and selects an MCS (Modulation andCoding Scheme) for each subcarrier. Namely, based on channel quality,the base station apparatus satisfies the desired communication quality(for example, lowest transmission rate, lowest error rate) for eachuser, allocates subcarriers so as to achieve the maximum frequencyutilization efficiency, and selects high-speed MCS for each subcarrier.This enables the implementation of a high throughput for a large numberof users.

An MCS selection table decided in advance is used in the selection ofMCS. The MCS selection table shows the correspondence between receptionquality such as CIR (Carrier to Interference Ratio) etc. and error ratessuch as PER (Packet Error rate) or BER (Bit Error Rate) etc. for everyMCS. During MCS selection, an MCS capable of satisfying the desirederror rate is selected based on the measured reception quality.

FIG. 1 is a view showing the relationship between frequency and time inthe case of allocating each item of data to a subcarrier block at thebase station apparatus. From FIG. 1, the base station apparatusallocates all data to subcarrier blocks #10 to #14 using scheduling.

However, in the case of carrying out scheduling and adaptive modulationfor every subcarrier block, it is necessary for communication terminalapparatus to report the CQI of every subcarrier to the base stationapparatus. This means that the amount of control information sent fromcommunication terminal apparatus to the base station apparatus isenormous and the transmission rate therefore falls. Further, it is alsonecessary for communication terminal apparatus to carry out processingto measure reception quality and generate the CQI, and for the basestation apparatus to carry out processing for scheduling and adaptivemodulation and such like for every subcarrier using the received CQI's.This means that the amount of signal processing occurring at the basestation apparatus and communication terminal apparatus is extremelylarge, which makes it difficult to achieve lower power consumption andhigh signal processing speed.

DISCLOSURE OF INVENTION

It is therefore the object of the present invention to provide wirelesscommunication apparatus and a subcarrier allocation method capable ofimproving transmission efficiency, achieving low power consumption, andachieving high-speed signal processing by selecting data for schedulingaccording to data type.

According to an aspect of the present invention, wireless communicationapparatus is comprised of a subcarrier allocation section allocatingfirst data satisfying predetermined conditions to subcarriers selectedby scheduling based on reception quality information indicatingreception quality of each communicating party and required transmissionrate information indicating required transmission rate of eachcommunicating party and allocating second data different to the firstdata to preassigned subcarriers, and a transmission section transmittingthe first data and the second data allocated to subcarriers by thesubcarrier allocation section.

According to a further aspect of the present invention, a base stationapparatus is provided with the wireless communication apparatus of thepresent invention.

According to a still further aspect of the present invention, asubcarrier allocation method comprises the steps of allocating firstdata satisfying predetermined conditions to subcarriers selected byscheduling based on reception quality information indicating receptionquality of each communicating party and required transmission rateinformation indicating required transmission rate of each communicatingparty, and allocating second data different to the first data topreassigned subcarriers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing allocation of data to subcarriers of therelated art.

FIG. 2 is a block view showing a configuration for a wirelesscommunication apparatus of a first embodiment of the present invention.

FIG. 3 is a block view showing a configuration for a communicationterminal apparatus of the first embodiment of the present invention.

FIG. 4 is a view showing allocation of data to subcarriers of the firstembodiment of the present invention.

FIG. 5 is a further view showing allocation of data to subcarriers ofthe first embodiment of the present invention.

FIG. 6A is another view showing allocation of data to subcarriers of thefirst embodiment of the present invention.

FIG. 6B is a view showing allocation of data to subcarriers of the firstembodiment of the present invention.

FIG. 7A is a further view showing allocation of data to subcarriers ofthe first embodiment of the present invention.

FIG. 7B is another view showing allocation of data to subcarriers of thefirst embodiment of the present invention.

FIG. 8 is a block view showing a configuration for a wirelesscommunication apparatus of a second embodiment of the present invention.

FIG. 9 is a flowchart showing operation of the wireless communicationapparatus of the second embodiment of the present invention.

FIG. 10 is a block view showing a configuration for a wirelesscommunication apparatus of a third embodiment of the present invention.

FIG. 11 is a flowchart showing operation of the wireless communicationapparatus of the third embodiment of the present invention.

FIG. 12 is a block view showing a configuration for a wirelesscommunication apparatus of a fourth embodiment of the present invention.

FIG. 13 is a flowchart showing operation of the wireless communicationapparatus of the fourth embodiment of the present invention.

FIG. 14 is a further flowchart showing operation of the wirelesscommunication apparatus of the fourth embodiment of the presentinvention.

FIG. 15 is a block view showing a configuration for a wirelesscommunication apparatus of a fifth embodiment of the present invention.

FIG. 16 is view showing allocation of data to subcarriers of the fifthembodiment of the present invention.

FIG. 17 is another view showing allocation of data to subcarriers of thefifth embodiment of the present invention.

FIG. 18 is a block view showing a configuration for a wirelesscommunication apparatus of a sixth embodiment of the present invention.

FIG. 19 is a block view showing a configuration for a wirelesscommunication apparatus of a seventh embodiment of the presentinvention.

FIG. 20 is a further flowchart showing operation of the wirelesscommunication apparatus of the seventh embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

The following is a detailed description with reference to the drawingsof preferred embodiments of the present invention.

(First Embodiment)

FIG. 2 is a block diagram showing a configuration for a wirelesscommunication apparatus 100 of a first embodiment of the presentinvention.

Transmission data processing sections 120-1 to 120-n are each comprisedof control information extraction section 105, demodulating section 106,decoding section 107, coding section 109, coding section 110,transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113 and modulatingsection 114. Transmission data processing sections 120-1 to 120-n areprovided for the number of users and each of transmission dataprocessing sections 120-1 to 120-n carries out processing ontransmission data transmitted to one user.

A reception radio processing section 102 down converts a signal receivedat an antenna 101 from a radio frequency to a baseband frequency tooutput to a guard interval (hereinafter referred to as “GI”) removingsection 103.

The GI removing section 103 removes a GI from a received signal inputtedfrom reception radio processing section 102 to output to a fast Fouriertransform (hereinafter referred to as “FFT) section 104.

After a received signal inputted by GI removing section 103 is convertedfrom serial data format to parallel data format, FFT section 104 carriesout FFT processing and outputs the result to each control informationextraction section 105 as a received signal for each user.

Control information extraction section 105 then extracts controlinformation from the received signal inputted by FFT section 104 tooutput to demodulating section 106.

Demodulating section 106 subjects control information inputted bycontrol information extraction section 105 to demodulation to output toa decoding section 107.

Decoding section 107 decodes the received signal inputted bydemodulating section 106 and outputs CQI's for each subcarrier containedin the received data after demodulation to control section 108. Further,decoding section 107 decodes a received signal inputted by demodulatingsection 106, outputs a NACK signal or ACK signal for transmission datasequence 1 contained in the received data after decoding to transmissionHARQ section 111 and outputs a NACK signal or ACK signal fortransmission data sequence 2 contained in the received data afterdecoding to transmission HARQ section 112.

Control section 108 constituting subcarrier and MCS allocation meansknows the number of useable subcarriers and the transmission raterequired by each communication terminal apparatus and therefore, inaccordance with the CQI's constituting reception quality information forthe communication terminal apparatus of each user inputted by decodingsection 107, selects subcarriers to which transmission data sequence 1is allocated using frequency scheduling and selects preassignedsubcarriers to which transmission data sequence 2 is allocated withoutcarrying out frequency scheduling in such a manner that transmissionrate required for each communication terminal apparatus is satisfied.Here, subcarriers transmission data sequence 1 is allocated to arelocalized subcarriers around a specific frequency within thecommunication frequency band width and subcarriers transmission datasequence 2 is allocated to are a plurality of subcarriers distributedover the whole of the communication frequency band width. Further, datafor transmission data sequence 1 is, for example, dedicated datatransmitted individually to the communication terminal apparatus of eachuser, and data for transmission data sequence 2 is, for example, commondata (for example, broadcast data or multicast data) transmitted incommon to the communication terminal apparatus for the plurality ofusers. Transmission data sequence 1 is not limited to dedicated data,and it is possible to use arbitrary data, from which effects offrequency scheduling and adaptive modulation can be obtained, such ashigh-speed data demanded of high-speed transfer or data transmitted tocommunication terminals during low speed movement and suchlike. Thetransmission data sequence 2 is also not limited to common data andarbitrary data such as data requiring continuous transmission at thesame transmission rate such as data for which the required transmissionspeed is low or data transmitted to communication terminal apparatusduring high-speed movement, or data for which effects of frequencyscheduling are low and bit error rate can be improved using frequencydiversity effects may be used.

Further, control section 108 appropriately selects MCS's for the M-arynumber and coding rates etc. using CQI's of the communication terminalapparatus of each user inputted by the decoding section 107 for thetransmission data sequence 1 subjected to frequency scheduling. Namely,control section 108 holds a table storing MCS selection informationcorrelating CQI and modulation schemes, and CQI and coding rate, andselects the modulation scheme and coding rate every subcarrier byreferring to MCS selection information using CQI for every subcarriersent from communication terminal apparatus of each user. Regarding thetransmission data sequence 1, control section 108 outputs coding rateinformation selected for each subcarrier to which the transmission datasequence 1 is allocated to the coding section 109 and outputs modulationscheme information selected for each subcarrier to which thetransmission data sequence 1 is allocated to modulating section 113.

Further, in the event that CQI's are not reported on by thecommunication terminal apparatus every subcarrier for the transmissiondata sequence 2 not subjected to frequency scheduling, control section108 uses a predetermined coding rate and a predetermined modulationscheme using the required transmission rate etc. Control section 108outputs coding rate information constituting the predetermined codingrate to coding section 110 and modulation scheme informationconstituting the predetermined modulation scheme to modulating section114. On the other hand, in the event that one item of CQI indicating anaverage reception quality of all subcarriers in a communicationfrequency band is inputted, control section 108 refers to the MCSselection information from the inputted CQI and selects an coding rateand modulation scheme, outputs the selected coding rate information tocoding section 110 and outputs the selected modulation schemeinformation to modulating section 114.

Further, control section 108 outputs information for subcarriers thetransmission data sequence 1 is allocated to by frequency scheduling tothe channel allocation section 115 and allocates preassigned subcarriersfor the transmission data sequence 2 that is not subjected to frequencyscheduling and outputs subcarrier information to channel allocationsection 116. Here, required transmission rate is, for example,information for the proportion of the amount of data per unit timerequired by a communication terminal apparatus of one user with respectto the amount of data per unit time required by all communicationterminal apparatus. The method of allocating transmission data sequence1 and transmission data sequence 2 to subcarriers is described in thefollowing.

Coding section 109 codes inputted transmission data sequence 1 (firstdata) and outputs this to transmission HARQ section 111 based on codingrate information inputted by control section 108.

Coding section 110 codes inputted transmission data sequence 2 (seconddata) and outputs this to transmission HARQ section 112 based on codingrate information inputted by control section 108.

Transmission HARQ section 111 outputs transmission data sequence 1inputted by coding section 109 to modulating section 113 and temporarilyholds transmission data sequence 1 outputted to modulating section 113.In the event that an NACK signal is inputted by decoding section 107,transmission HARQ section 111 outputs temporarily stored transmissiondata sequence 1 for which output is complete to modulating section 113again due to a retransmission request by a communication terminalapparatus. On the other hand, in the event that an ACK signal isinputted by decoding section 107, transmission HARQ section 111 outputsnew transmission data to modulating section 113.

Transmission HARQ section 112 outputs transmission data sequence 2inputted by coding section 110 to modulating section 114 and temporarilyholds transmission data sequence 1 outputted to modulating section 114.In the event that an NACK signal is inputted by decoding section 107,transmission HARQ section 112 outputs temporarily stored transmissiondata sequence 2 for which output is complete to modulating section 114again due to a retransmission request by a communication terminalapparatus. On the other hand, in the event that an ACK signal isinputted by decoding section 107, transmission HARQ section 112 outputsnew transmission data to modulating section 114.

Modulating section 113 modulates transmission data sequence 1 inputtedby transmission HARQ section 111 based on modulation scheme informationinputted by control section 108 and outputs this to channel allocationsection 115.

Modulating section 114 modulates transmission data sequence 2 inputtedby transmission HARQ section 112 based on modulation scheme informationinputted by control section 108 and outputs this to channel allocationsection 116.

Channel allocation section 115 allocates transmission data sequence 1inputted by modulating section 113 to subcarriers based on subcarrierinformation inputted by control section 108 and outputs this to InverseFast Fourier Transform (hereinafter abbreviated to “IFFT”) section 117.

Channel allocation section 116 allocates transmission data sequence 2inputted by modulating section 114 to subcarriers based on subcarrierinformation inputted by control section 108 and outputs this to IFFTsection 117.

IFFT section 117 subjects transmission data sequence 1 inputted bychannel allocation section 115 and transmission data sequence 2 inputtedby channel allocation section 116 to inverse fast Fouriertransformation, and outputs this to GI insertion section 118.

GI insertion section 118 inserts GI's into transmission data sequence 1and transmission data sequence 2 inputted by IFFT section 117 andoutputs this to transmission wireless processing section 119.

Transmission wireless processing section 119 upconverts etc.transmission data sequence 1 and transmission data sequence 2 inputtedfrom GI insertion section 118 from a baseband frequency to a radiofrequency for transmission from antenna 101. Wireless communicationapparatus 100 transmits control information to communication terminalapparatus by coding control data using an coding section (not shown) andmodulating control information using a modulating section (not shown).Here, control information is constituted of modulation schemeinformation, coding rate information, and scheduling informationconstituted by allocated subcarrier information, etc. Further, controlinformation can be transmitted prior to continuous data transmission ormay be transmitted as one of the transmission data sequence 2 at thesame time as data transmission.

Next, a description is given of a configuration for communicationterminal apparatus 200 using FIG. 3. FIG. 3 is a block diagram showing aconfiguration for communication terminal apparatus 200.

A reception radio processing section 202 down converts a signal receivedat an antenna 201 from a radio frequency to a base band frequency etc.,for output to a GI removal section 203.

GI removal section 203 removes GI from the received signal inputted byreception radio processing section 202 for output to an FFT section 204.

After a received signal inputted by GI removing section 203 is convertedfrom a serial data format to a parallel data format, FFT section 204despreads each item of data converted to parallel data format using adespreading code, subjects this to fast Fourier transform, and outputsthis to demodulating section 205 and reception quality measuring section206.

Demodulating section 205 demodulates the received signal inputted by FFTsection 204 and outputs this to reception HARQ section 207.

Reception quality measuring section 206 measures reception quality usingthe received signal inputted by FFT section 204 and outputs measuredreception quality information to CQI generating section 213. Namely,reception quality measuring section 206 obtains a measurement valueindicating an arbitrary reception quality such as CIR (Carrier toInterference Ratio) or SIR (Signal to Interference Ratio) etc. andoutputs the obtained measurement value to CQI generating section 213 asreception quality information.

If the received signal inputted by demodulating section 205 is new data,reception HARQ section 207 saves all or part of the received signal andoutputs the received signal to decoding section 208. If the receivedsignal is retransmitted data, the saving takes place after combiningwith a received signal saved previously and the combined received signalis outputted to decoding section 208.

Decoding section 208 decodes the received signal inputted by receptionHARQ section 207 and outputs this as user data. Further, decodingsection 208 performs error detection and decoding and outputs this tocontrol information determining section 209 and ACK/NACK generatingsection 210. The error detection may use CRC (Cyclic Redundancy Checks).This error detection is not limited to CRC and arbitrary error detectionmethods may also be applied.

Control information determining section 209 extracts control informationfrom the received signal inputted by decoding section 208 and determineswhether or not user data for its own address has been subjected tofrequency scheduling using the extracted control information. In theevent that frequency scheduling has taken place, control informationdetermining section 209 controls CQI generating section 213 in order togenerate CQI for each subcarrier. In the event that frequency schedulinghas not taken place, control information determining section 209controls CQI generating section 213 so that CQI is not generated, orcontrols CQI generating section 213 in such a manner that one item ofCQI indicating reception quality averaged for all of the subcarrierswithin the communication frequency band is generated. In this case,frequency scheduling not having taken place means that preassignedsubcarriers have been allocated by wireless communication apparatus 100.

ACK/NACK generating section 210 generates a NACK signal constituting anerror determination signal if retransmission is necessary using errordetection results information inputted by decoding section 208,generates an ACK signal constituting an error determination signal inthe event that retransmission is not necessary, and outputs thegenerated NACK signal and ACK signal to an coding section 211.

Coding section 211 codes a NACK signal or ACK signal inputted byACK/NACK generating section 210 to output to modulating section 212.

Modulating section 212 modulates a NACK signal or ACK signal inputted bycoding section 211 for output to multiplexer 216.

In the event that frequency scheduling has taken place, and in the casethat CQI generating section 213 has been controlled so that CQI isgenerated by control information determining section 209, CQI generatingsection 213 compares reception quality information inputted by receptionquality measuring section 206 and a plurality of CQI selection thresholdvalues set according to reception quality, and selects and generates CQIfor each subcarrier. Namely, CQI generating section 213 has a referencetable saving information for CQI selection use to which different CQI'sare assigned every predetermined region for measurement valuesindicating reception quality separated by the plurality of CQI selectionthreshold values and selects CQI's by referring to information for CQIselection use employing reception quality information inputted by areception quality measuring section 206. CQI generating section 213generates one CQI for one subcarrier. CQI generating section 213 outputsthe generated CQI's to coding section 214. In the event that frequencyscheduling has not taken place and in the case that CQI generatingsection 213 has been controlled so as to generate CQI indicating averagereception quality for all of the subcarriers within a communicationfrequency band by control information determining section 209, CQIgenerating section 213 obtains average reception quality from receptionquality information for each carrier inputted by reception qualitymeasuring section 206 and outputs one item of CQI indicating theobtained average reception quality to coding section 214. On the otherhand, in the event that frequency scheduling has not taken place, and inthe case that CQI generating section 213 has been controlled so that CQIis not generated by control information determining section 209, CQIgenerating section 213 does not generate CQI.

Coding section 214 codes CQI inputted by CQI generating section 213 andoutputs this to modulating section 215.

Modulating section 215 modulates CQI's inputted by coding section 214for output to a multiplexer 216.

Multiplexer 216 multiplexes CQI inputted by modulating section 215 andNACK signals or ACK signals inputted by modulating section 212 andoutputs generated transmission data to IFFT section 217. In the eventthat CQI is not inputted by modulating section 215, multiplexer 216outputs just an ACK signal or NACK signal to IFFT section 217.

IFFT section 217 subjects transmission data inputted by multiplexer 216to inverse fast Fourier transform and outputs this to GI insertionsection 218.

GI insertion section 218 inserts GI's into transmission data inputtedfrom IFFT section 217 for output to a transmission radio processingsection 219.

Transmission radio processing section 219 upconverts etc. transmissiondata inputted from GI insertion section 218 from a baseband frequency toa radio frequency for transmission to antenna 201.

A description is given for wireless communication apparatus 100 andcommunication terminal apparatus 200 where a subcarrier is taken as aunit of allocation but it is also possible to adopt subcarrier blocks orresource blocks where pluralities of subcarriers are collected together.

Next, a description is given using FIG. 4 and FIG. 5 of a method ofallocating subcarriers at wireless communication apparatus 100. FIG. 4is a view showing a relationship between frequency and time in the eventthat transmission data sequence 1 and transmission data sequence 2 arefrequency-multiplexed every frame, and FIG. 5 is a view showing arelationship between frequency and time in the event that transmissiondata sequence 1 and transmission data sequence 2 are time-multiplexedevery frame.

Here, when frequency scheduling and adaptive modulation is carried outevery subcarrier, the amount of control information is huge, and theamount of signal processing taking place at wireless communicationapparatus 100 and communication terminal apparatus 200 is enormous.Typically, subcarrier blocks are adopted where a plurality ofconsecutive subcarriers where correlation of fading fluctuation is highare collected together, with frequency scheduling and adaptivemodulation then taking place in subcarrier block units.

First, a description is given of the case where transmission datasequence 1 and transmission data sequence 2 are frequency-multiplexed.From FIG. 4, at a predetermined communication frequency band, data oftransmission data sequence 1 transmitted to communication terminalapparatus of user 1 is allocated to subcarrier block #301, data oftransmission data sequence 1 to be transmitted to communication terminalapparatus of user 2 is allocated to subcarrier block #305, and data oftransmission data sequence 1 to be transmitted to communication terminalapparatus of user n is allocated to subcarrier block #306. On the otherhand, data for transmission data sequence 2 transmitted in common tocommunication terminal apparatuses of a plurality of users arbitrarilyselected from users 1 to n is allocated to time-multiplexed channels#302, #303, #304, and channel #302, #303, #304 are allocated tosubcarriers between subcarrier blocks #301, #305, #306. Channel #302,#303, #304 are allocated to a plurality of subcarriers distributed overthe whole of the communication frequency band. As a result, frequencydiversity effects are obtained for data for transmission data sequence2. In this event, the frequency diversity effect is greater for a largernumber of allocated subcarriers and a greater spread of subcarrierfrequencies.

Next, a description is given of the case where transmission datasequence 1 and transmission data sequence 2 are time-multiplexed. In afirst method of time-multiplexing transmission data sequence 1 andtransmission data sequence 2, from FIG. 5, in a predeterminedcommunication frequency band, data for transmission data sequence 1 tobe transmitted to communication terminal apparatus of user 1 isallocated to subcarrier block #404, data for transmission data sequence1 to be transmitted to communication terminal apparatus of user 2 isallocated to subcarrier block #405, and data for transmission datasequence 1 to be transmitted to communication terminal apparatus of usern is allocated to subcarrier block #406. On the other hand, data fortransmission data sequence 2 transmitted in common to communicationterminal apparatuses of a plurality of users arbitrarily selected fromusers 1 to n is allocated to frequency-multiplexed channels #401, #402,#403. Channels #401, #402, #403 are allocated to a plurality ofsubcarriers distributed over the whole of the communication frequencyband. As a result, frequency diversity effects are obtained for data fortransmission data sequence 2. In this event, the frequency diversityeffect is greater for a larger number of allocated subcarriers and agreater spread of subcarrier frequencies.

Further, in a second method for time-multiplexing transmission datasequence 1 and transmission data sequence 2, channel configuration isset in time slot units. A time slot for transmitting transmission datasequence 1 that has been subjected to frequency scheduling and a timeslot for transmitting transmission data sequence 2 that has not beensubjected to frequency scheduling are decided in advance. The number oftime slots allocated to the data of transmission data sequence 1 and thenumber of time slots allocated to data for transmission data sequence 2is then changed according to the amount of traffic, properties of thetransmission data sequence, and propagation path environment. Forexample, when it is demanded to reduce resources allocated totransmission data sequence 1 and to increase resources allocated totransmission data sequence 2 with the channel configuration shown inFIG. 4 and FIG. 5, the number of bits it is possible to transmit withone channel (for example, subcarrier block #301) for respective MCS's isreduced, and it is necessary to change the amount of data transmittedfor upper layers such as control stations, etc. This means that theinfluence on other functions is substantial and complex control becomesnecessary. However, as with the second method, if channel configurationis set in advance using time slot units, it is possible to simply changethe number of time slots. The number of bits transmitted by one channeltherefore does not change and it can be ensured that there is noinfluence on other functions with straightforward control.

Next, a description is given of a method for allocating transmissiondata sequence 1 and transmission data sequence 2 to each subcarrier, andthe influence of fluctuation in SIR in the event of transmitting each oftransmission data sequence 1 and transmission data sequence 2 allocatedto subcarriers using FIG. 6A, FIG. 6B, FIG. 7A and FIG. 7B. The methodsof allocating transmission data sequence 1 and transmission datasequence 2 to subcarriers can be considered to be the two methods ofFIG. 6A, B and FIG. 7A, B. FIG. 6A, B show the case of allocatingtransmission data sequence 1 to subcarriers using frequency schedulingand allocating transmission data sequence 2 only to localizedsubcarriers of a specific frequency. Further, FIG. 7A, B show the caseof allocating transmission data sequence 1 to subcarriers usingfrequency scheduling and allocating transmission data sequence 2 to aplurality of subcarriers distributed over the whole of the communicationfrequency band. In FIG. 6A, FIG. 6B, FIG. 7A and FIG. 7B, the verticalaxis is received SIR, with fluctuations occurring in the frequencydirection due to frequency-selective fading.

First, a description is given of the case in FIG. 6A, B wheretransmission data sequence 1 is allocated to subcarriers usingscheduling and transmission data sequence 2 is only allocated tolocalized subcarriers around a specific frequency. As shown in FIG. 6A,at time T1, data #501 for transmission data sequence 1 is allocated onlyto subcarriers for part of the communication frequency band byscheduling, and data #502 for transmission data sequence 2 is allocatedonly to localized subcarriers around a specific frequency decided inadvance.

As shown in FIG. 6B, at time T2, SIR for a frequency of subcarriers thedata #502 of transmission data sequence 2 is allocated to falls downfurther than at time T1 due to fading fluctuation, and data #501 fortransmission data sequence 1 is allocated to subcarriers of superiorreception quality different from the subcarriers at a time T1 usingscheduling. On the other hand, data #502 for transmission data sequence2 is allocated to subcarriers determined in advance. Allocation to thesame subcarrier therefore remains the case even if SIR drops. In thisway, in the event that data #502 for transmission data sequence 2 isallocated only to localized subcarriers around a specific frequency,when the SIR drops for a long period of time, the effectiveness of errorcorrection coding is also reduced, and the possibility that data #502for transmission data sequence 2 will not be decoded without errors atcommunication terminal apparatus is high.

Next, a description is given of the case of FIG. 7A, B wheretransmission data sequence 1 is allocated to subcarriers using frequencyscheduling and transmission data sequence 2 is allocated to a pluralityof subcarriers distributed over the whole of the communication frequencyband. As shown in FIG. 7A, at time T1, data #602 for transmission datasequence 1 is allocated only to subcarriers for part of thecommunication frequency band by scheduling, and data #601 a to #601 e oftransmission data sequence 2 is allocated to a plurality of subcarriersdistributed over the whole of the communication frequency band decidedin advance. At time T1, the SIR for the frequency of the subcarriersdata #601 e is allocated to drops due to fading fluctuation but the SIRfor the frequency of the subcarriers data #601 a to #601 d constitutingthe same data is allocated to does not drop. The communication terminalapparatus is therefore capable of receiving data #601 a to #601 e fortransmission data sequence 2 without error using the results of errorcorrection coding. Further, data #602 for transmission data sequence 1is allocated to subcarriers of frequencies for which the SIR does notdrop due to scheduling.

As shown in FIG. 7B, at time T2, in the event that the propagationenvironment changes, the SIR of frequencies for subcarriers data #601 eand data #601 b are allocated to drops due to fading fluctuation but theSIR for frequencies the subcarriers data #601 a, #601 c, #601 dconstituting the same data are allocated to does not drop. Because ofthis, while signal receiving processing is carried out at communicationterminal apparatus, it is possible to decode data for transmission datasequence 2 that also includes data for data #601 e and data #601 bwithout error using the results of error correction coding. Further,data #502 of transmission data sequence 1 is allocated to subcarriers offrequencies for which SIR does not drop different from subcarriers offrequencies to which allocated at time T1 using scheduling.

According to this first embodiment, transmission data sequence 1 isallocated to subcarriers using scheduling and transmission data sequence2 is allocated to preassigned subcarriers. It is therefore not necessaryfor CQI to be sent from communication terminal apparatus transmittingtransmission data sequence 2 every subcarrier. This means thattransmission rate can be improved because the amount of controlinformation can be reduced with respect to the amount of transmissiondata.

Further, according to this first embodiment, it is not necessary togenerate CQI every subcarrier at communication terminal apparatustransmitting transmission data sequence 2 and it is not necessary toperform scheduling and subcarrier allocation for transmission datasequence 2 at base station apparatus. This means it is possible toachieve high-speed signal processing at the base station apparatus andthe communication terminal apparatus.

Moreover, according to the first embodiment, frequency diversity effectsare obtained by distributing a plurality of subcarriers over the wholeof the communication frequency band and allocating transmission datasequence 2. It is therefore possible to improve error ratecharacteristics as a result of fading fluctuation etc. not exerting anyinfluence and the number of retransmissions can be reduced. It istherefore possible to improve overall throughput.

Further, in the event that the number of time slots for transmittingtransmission data sequence 1 and the number of time slots fortransmitting transmission data sequence 2 are changed according to theamount of traffic etc., this can be achieved simply by increasing orreducing the number of time slots for transmitting each item of data andprocessing can therefore be simplified.

(Second Embodiment)

FIG. 8 is a block diagram showing a configuration for wirelesscommunication apparatus 700 of a second embodiment of the presentinvention.

As shown in FIG. 8, wireless communication apparatus 700 of this secondembodiment is wireless communication apparatus 100 of the firstembodiment shown in FIG. 2 with data amount measuring section 701 andused channel determination section 702 added. In FIG. 8, portions withthe same configuration as for FIG. 2 are given the same numerals and arenot described.

Transmission data processing sections 703-1 to 703-n are eachconstituted by control information extraction section 105, demodulatingsection 106, decoding section 107, coding section 109, coding section110, transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113, modulatingsection 114, data amount measuring section 701, and used channeldetermination section 702. Transmission data processing sections 703-1to 703-n are provided for just the number of users and each of thetransmission data processing sections 703-1 to 703-n carries outprocessing on transmission data transmitted to one user.

Data amount measuring section 701 measures the amount of data fortransmission data and outputs measurement results to used channeldetermination section 702. Data amount measuring section 701 measuresthe amount of data before starting data transmission in order tosimplify control. Data is then transmitted using the same used channeluntil transmission is complete. Data amount measuring section 701notifies communication terminal apparatus of measurement results beforestarting transmission.

Used channel determination section 702 then compares measurement resultsinput by data amount measuring section 701 and a threshold value andselects a channel for use. Namely, if the measurement results aregreater than or equal to the threshold value, used channel determinationsection 702 selects a data channel allocated to subcarriers of goodreception quality using frequency scheduling and outputs this to codingsection 109 as data for transmission data sequence 1. If the measurementresults are less than the threshold value, used channel determinationsection 702 selects a data channel allocated to preassigned subcarriersand outputs this to coding section 110 as data for transmission datasequence 2.

Next, a description is given of the operation of the wirelesscommunication apparatus 700 using FIG. 9. FIG. 9 is a flowchart showingthe operation of wireless communication apparatus 700.

First, data amount measuring section 701 measures the amount of data(step ST801).

Next, used channel determination section 702 compares the measuredamount of data and a threshold value, and determines whether or not theamount of data is greater than or equal to the threshold value (stepST802).

In the event that the amount of data is greater than or equal to athreshold value, used channel determination section 702 determinesallocation of data to subcarriers of superior reception quality (stepST803).

On the other hand, in the event that the amount of data is less than thethreshold value, used channel determination section 702 determinesallocation of data to preassigned subcarriers (fixed allocation) (stepST804).

Next, wireless communication apparatus 700 transmits data allocated tosubcarriers (step ST805). With the exception of data where the amount ofdata is greater than or equal to a threshold value being allocated tosubcarrier blocks and data where the amount of data is less than athreshold value being allocated to preassigned subcarriers, the methodof allocating data to each subcarrier is the same as for FIG. 4 and FIG.5 and is therefore not described.

According to the second embodiment of the invention, in addition to theeffects of the first embodiment, it is possible to allocate data forwhich the amount of data is extremely large to subcarriers of superiorquality using frequency scheduling and perform modulation using amodulation scheme with a large M-ary number. It is therefore possible totransmit large amounts of data at high speed and communication terminalapparatus receiving the data can decode the data without error.

Moreover, according to this second embodiment, data for which the amountof data is small is allocated to a plurality of subcarriers decided inadvance over the whole of the communication frequency band. It istherefore not necessary to transmit CQI from communication terminalapparatus every subcarrier and the amount of control information can bereduced with respect to the amount of transmission data. It is thereforepossible to increase transmission efficiency. Further, communicationterminal apparatus receiving data are capable of decoding data withouterror using the frequency diversity effect.

(Third Embodiment)

FIG. 10 is a block diagram showing a configuration for a wirelesscommunication apparatus 900 of a third embodiment of the presentinvention.

As shown in FIG. 10, wireless communication apparatus 900 of this thirdembodiment is wireless communication apparatus 100 of the firstembodiment shown in FIG. 2 with pilot signal extraction section 901,movement speed estimation section 902 and used channel determinationsection 903 added. In FIG. 10, portions with the same configuration asfor FIG. 2 are given the same numerals and are not described.

Transmission data processing sections 904-1 to 904-n are each comprisedof control information extraction section 105, demodulating section 106,decoding section 107, coding section 109, coding section 110,transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113, modulatingsection 114, pilot signal extraction section 901, movement speedestimation section 902, and used channel determination section 903.Transmission data processing sections 904-1 to 904-n are provided forjust the number of users and each of the transmission data processingsections 904-1 to 904-n carries out processing on transmission datatransmitted to one user.

Pilot signal extraction section 901 extracts a pilot signal from areceived signal of communication terminal apparatus inputted by FFTsection 104 and outputs this to movement speed estimation section 902.

Movement speed estimation section 902 obtains the amount of fadingfluctuation of the pilot signal using the pilot signal inputted by pilotsignal extraction section 901 and estimates movement speed ofcommunication terminal apparatus using the obtained amount offluctuation. Movement speed estimation section 902 then outputs movementspeed information for communication terminal apparatus to used channeldetermination section 903 as estimation results.

Used channel determination section 903 then compares movement speedinformation input by movement speed estimation section 902 with athreshold value to select a channel for use. Namely, if the estimatedspeed of movement of a communication partner is less than the thresholdvalue, used channel determination section 903 selects a data channelallocated to subcarriers of good reception quality using frequencyscheduling and outputs this to coding section 109 as data fortransmission data sequence 1. If the estimated speed of movement of thecommunication partner is greater than or equal to the threshold value,used channel determination section 903 selects a data channel allocatedto preassigned subcarriers and outputs this to coding section 110 asdata for transmission data sequence 2.

Next, a description is given of the operation of wireless communicationapparatus 900 using FIG. 11. FIG. 11 is a flowchart showing theoperation of wireless communication apparatus 900.

First, pilot signal extraction section 901 extracts a pilot signal froma received signal and movement speed estimation section 902 estimatesmovement speed of communication terminal apparatus from the amount offluctuation of fading of the extracted pilot signal (step ST1001).

Next, used channel determination section 903 compares the estimatedmovement speed and a threshold value, and determines whether or not themovement speed is less than the threshold value (step ST1002).

In the event that the movement speed is less than the threshold value,control section 108 determines allocation of data to subcarriers ofsuperior reception quality using frequency scheduling (step ST1003). Thereason frequency scheduling is used in the case where movement speed isless than the threshold value is that the accuracy of CQI duringadaptive allocation of subcarriers at control section 108 is good incases where speed of fading fluctuation due to movement of thecommunication terminal apparatus is sufficiently small compared to theperiod in which CQI reporting is given by communication terminalapparatus and frequency scheduling is therefore effective.

On the other hand, in the event that the movement speed is not less thanthe threshold value, control section 108 determines allocation of datato preassigned subcarriers (fixed allocation) (step ST1004). The reasonwhy frequency scheduling is not used in the case where movement speed isnot less than the threshold value (in cases where the movement speed isgreater than or equal to a threshold value) is that the accuracy of CQIduring adaptive allocation of subcarriers at control section 108 is poorin cases where speed of fading fluctuation due to movement of thecommunication terminal apparatus is large compared to the period inwhich CQI reporting is given by communication terminal apparatus, anddeterioration therefore occurs due to frequency scheduling. In thisevent, more efficient transmission is possible by using channelsallocated in a fixed manner such as obtained with frequency diversity,where CQI is not necessary every subcarrier.

Next, wireless communication apparatus 900 transmits data allocated tosubcarriers (step ST1005). With the exception of data to be transmittedto communication terminal apparatus of a movement speed of less than athreshold value being allocated to subcarrier blocks and data to betransmitted to communication terminal apparatus of a movement speed inexcess of a threshold value being allocated to preassigned subcarriers,the method of allocating data to each subcarrier is the same as for FIG.4 and FIG. 5 and is therefore not described.

According to the third embodiment of the invention, in addition to theeffects of the first embodiment, it is possible to allocate data to betransmitted to communication terminal apparatus of a low movement speedto subcarriers of superior quality using frequency scheduling andperform modulation using a modulation scheme with a large M-ary number.It is therefore possible to transmit data at high speed in an efficientmanner and communication terminal apparatus receiving the data candemodulate the data without error.

Further, according to the third embodiment, data transmitted tocommunication terminal apparatus of a high movement speed is allocatedto a plurality of preassigned subcarriers over the whole of thecommunication frequency band. Thus, communication terminal apparatusreceiving the data is capable of demodulating the data without errorusing the frequency diversity effect.

In the third embodiment, movement speed of communication terminalapparatus is estimated and compared to a threshold value, but this is byno means limiting and fading speed in a time direction may be estimatedand compared to a threshold value. Further, it is also possible toreport movement speed information from communication terminal apparatus.

(Fourth Embodiment)

FIG. 12 is a block view showing a configuration for a wirelesscommunication apparatus 1100 of a fourth embodiment of the presentinvention.

As shown in FIG. 12, wireless communication apparatus 1100 of thisfourth embodiment is wireless communication apparatus 100 of the firstembodiment shown in FIG. 2 with pilot signal extraction section 1101,delay spread measurement section 1102 and used channel determinationsection 1103 added. In FIG. 12, portions with the same configuration asfor FIG. 2 are given the same numerals and are not described.

Transmission data processing sections 1104-1 to 1104-n are eachcomprised of control information extraction section 105, demodulatingsection 106, decoding section 107, coding section 109, coding section110, transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113, modulatingsection 114, pilot signal extraction section 1101, delay spreadmeasurement section 1102, and used channel determination section 1103.Transmission data processing sections 1104-1 to 1104-n are provided forjust the number of users and each of the transmission data processingsections 1104-1 to 1104-n carries out processing on transmission datatransmitted to one user.

Pilot signal extraction section 1101 extracts a pilot signal from areceived signal of communication terminal apparatus inputted by FFTsection 104 and outputs this to delay spread measurement section 1102.

Delay spread measurement section 1102 measures delay spread using apilot signal inputted by pilot signal extraction section 1101. Delayspread measurement section 1102 outputs results of measuring delayspread to used channel determination section 1103.

Used channel determination section 1103 compares delay spread given bythe results of measuring delay spread of a propagation path inputted bydelay spread measurement section 1102 with an upper threshold value, andcompares delay spread with and a lower threshold value. In the eventthat delay spread is greater than or equal to the lower threshold valueand is less than the upper threshold value, used channel determinationsection 1103 outputs inputted transmission data to coding section 109 asdata of transmission data sequence 1. In the event that delay spread isless than the lower threshold value or is greater than or equal to theupper threshold value, used channel determination section 1103 outputsinputted transmission data to coding section 110 as data of transmissiondata sequence 2. It is also possible for used channel determinationsection 1103 to compare delay spread of a propagation path with onethreshold value, rather than with an upper threshold value and a lowerthreshold value. Namely, used channel determination section 1103 maycompare delay spread given by results of measuring delay spread of apropagation path inputted by delay spread measurement section 1102 and athreshold value, and may output inputted transmission data to codingsection 109 as data for transmission data sequence 1 in the event thatdelay spread is greater than or equal to a threshold value, and outputinputted transmission data to coding section 110 as data fortransmission data sequence 2 in the event that delay spread is less thana threshold value.

Next, a description is given using FIG. 13 of the operation of wirelesscommunication apparatus 1100 in the case of allocating transmission datato subcarriers based on results of comparing delay spread, an upperorder threshold value, and a lower order threshold value. FIG. 13 is aflowchart showing the operation of wireless communication apparatus1100.

First, pilot signal extraction section 1101 extracts a pilot signalusing a reception signal and delay spread measurement section 1102measures delay spread using an extracted pilot signal (step ST1201).

Next, used channel determination section 1103 compares the measureddelay spread wiht a lower threshold value, then determines whether ornot delay spread is greater than or equal to a lower threshold value(step ST1202).

In the event that the delay spread is less than the lower thresholdvalue, used channel determination section 1103 outputs transmission datato coding section 110, and control section 108 determines to allocatedata to preassigned subcarriers (fixed allocation) (step ST1203).

On the other hand, in the event that delay spread is greater than orequal to the lower threshold value in step ST1202, used channeldetermination section 1103 determines whether or not the delay spread isless than the upper threshold value (step ST1204).

In the event that the delay spread is less than the upper thresholdvalue, used channel determination section 1103 outputs the transmissiondata to coding section 110, and control section 108 determinesallocation of data to subcarriers of superior reception quality usingfrequency scheduling (step ST1205).

In the event that delay spread is not less than the upper thresholdvalue in step ST1204, control section 108 determines allocation of datato preassigned subcarriers (fixed allocation) (step ST1203).

Next, wireless communication apparatus 1100 transmits data allocated tosubcarriers (step ST1206).

Next, a description is given using FIG. 14 of the operation of wirelesscommunication apparatus 1100 in the case of allocating transmission datato subcarriers based on results of comparing delay spread and athreshold value. FIG. 14 is a flowchart showing the operation ofwireless communication apparatus 1100.

First, pilot signal extraction section 1101 extracts a pilot signalusing a reception signal and delay spread measurement section 1102measures delay spread using an extracted pilot signal (step ST1301).

Next, used channel determination section 1103 determines whether or notmeasured delay spread is greater than or equal to a threshold value(step ST1302).

In the event that the delay spread is greater than or equal to thethreshold value, used channel determination section 1103 outputs thetransmission data to coding section 109, and control section 108determines allocation of data to subcarriers of superior receptionquality using frequency scheduling (step ST1303).

On the other hand, in the event that the delay spread is not greaterthan or equal to the threshold value, used channel determination section1103 outputs transmission data to coding section 110, and controlsection 108 determines to allocation of data to preassigned subcarriers(fixed allocation) (step ST1304).

Next, wireless communication apparatus 1100 transmits data allocated tosubcarriers (step ST1305).

A description is now given of the reason frequency scheduling is notused in the event that propagation path delay spread is less than thethreshold value, or in the case that propagation path delay spread isless than a lower threshold value or greater than or equal to an upperthreshold value. Regarding a property of a propagation path, in theevent that delay spread is small, fluctuations in fading in thefrequency direction become smooth, with fluctuations becoming moresevere for a large delay spread. In the event that propagation pathdelay spread is small and fading fluctuation in a frequency directionwithin subcarrier blocks for transmission data sequence 1 in FIG. 6 andFIG. 7 is small (in the case of smooth fluctuation), from the viewpointof average reception quality within subcarrier blocks, the differencebetween superior subcarrier blocks and inferior subcarrier blocks issubstantial, and the frequency scheduling effect is large. On the otherhand, when propagation path delay spread is too small, there is almostno fading fluctuation in the frequency direction within the whole of theused frequency band and the same reception quality is attained for allsubcarrier blocks, with the frequency scheduling effect thereforedisappearing. Frequency scheduling is therefore employed when thepropagation path delay spread is in the range described above. Further,in the event that the propagation path delay spread is large, fadingfluctuation within the subcarrier blocks of FIG. 6A, FIG. 6B, FIG. 7Aand FIG. 7B is large, and reception quality is substantially the samefor all subcarrier blocks from the viewpoint of average receptionquality within subcarrier blocks. In this case, there is almost nofrequency scheduling effect, and transmission efficiency falls by givingCQI reporting for every subcarrier. Similarly, when propagation pathdelay spread is small, there is no frequency scheduling effect becausethere is no difference in the reception quality of the subcarrierblocks.

With the exception of data where the delay spread is greater than orequal to a threshold value or data where delay spread is greater than orequal to a lower order threshold value and less than an upper orderthreshold value being allocated to subcarrier blocks and data where thedelay spread is less than a threshold value or data where the delayspread is less than a lower order threshold value and greater than orequal to an upper order threshold value being allocated to subcarriersdetermined in advance, the method of allocating data to each subcarrieris the same as for FIG. 4 and FIG. 5 and is therefore not described.

According to the fourth embodiment, in addition to the effects of thefirst embodiment, in the event that delay spread is greater than orequal to a threshold value, or in the event that delay spread is greaterthan or equal to a lower threshold value and less than an upperthreshold value, transmission data is allocated to subcarriers ofsuperior quality using scheduling. Therefore, in the event that thedifference in reception quality every subcarrier block is large in orderto smooth out fluctuations in fading, and the effects of frequencyscheduling are therefore large as a result of allocating transmissiondata to be transmitted to users using a large amount of data beingallocated to subcarrier blocks of superior reception quality.

Further, according to the fourth embodiment, in the case of using anupper threshold value and a lower threshold value, scheduling is notcarried out in the event that delay spread where the difference betweenreception quality of each subcarrier blocks is small is less than alower threshold value. It is therefore possible to make the amount ofcontrol information small and increase transmission efficiency as aresult of it not being necessary for communication terminal apparatus totransmit CQI.

(Fifth Embodiment)

FIG. 15 is a block diagram showing a configuration for a wirelesscommunication apparatus 1400 of a fifth embodiment of the presentinvention.

As shown in FIG. 15, wireless communication apparatus 1400 of this fifthembodiment is wireless communication apparatus 100 of the firstembodiment shown in FIG. 2 with channel configuration control section1401 added. In FIG. 15, portions with the same configuration as for FIG.2 are given the same numerals and are not described.

Transmission data processing sections 1402-1 to 1402-n are eachcomprised of control information extraction section 105, demodulatingsection 106, decoding section 107, coding section 109, coding section110, transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113 and modulatingsection 114. Transmission data processing sections 1402-1 to 1402-n areprovided for just the number of users and each of the transmission dataprocessing sections 1402-1 to 1402-n carries out processing ontransmission data transmitted to one user.

Channel configuration control section 1401 measures the amount of dataand required transmission speed for user data transmitted to eachcommunication terminal apparatus and calculates a ratio for the numberof low speed data and the number of high speed data (stream numberratio). Channel configuration control section 1401 then sets channelconfiguration in such a manner that a ratio of high-speed data channelsand low-speed data channels is the same as the calculated number ratioand outputs the channel configuration information to channel allocationsection 115 and channel allocation section 116.

Channel allocation section 115 allocates transmission data sequence 1constituted by high-speed data inputted by modulating section 113 tosubcarriers for output to IFFT section 117 based on channelconfiguration information inputted by channel configuration controlsection 1401 and subcarrier information inputted by control section 108.

Channel allocation section 116 allocates transmission data sequence 2constituted by low-speed data inputted by modulating section 114 tosubcarriers for output to IFFT section 117 based on channelconfiguration information inputted by channel configuration controlsection 1401 and subcarrier information inputted by control section 108.

Next, a description is given using FIG. 4, FIG. 5, FIG. 16 and FIG. 17of a method of allocating subcarriers at wireless communicationapparatus 1400. FIG. 16 is a view showing a relationship betweenfrequency and time in the event that transmission data sequence 1(high-speed data) and transmission data sequence 2 (low speed data) arefrequency-multiplexed every frame, and FIG. 17 is a view showing arelationship between frequency and time in the event that transmissiondata sequence 1 (high-speed data) and transmission data sequence 2(low-speed data) are time-multiplexed every frame.

First, a description is given of the case where transmission datasequence 1 and transmission data sequence 2 are frequency-multiplexed.FIG. 16 shows the case where the proportion of low-speed data in thenumber ratio for low-speed data and high-speed data is larger than forFIG. 4, with FIG. 16 showing six low-speed data channels to the threelow-speed data channels of FIG. 4.

From FIG. 16 at a predetermined communication frequency band width, dataof transmission data sequence 1 transmitted to communication terminalapparatus of user 1 is allocated to subcarrier block #1501, data oftransmission data sequence 1 to be transmitted to communication terminalapparatus of user 2 is allocated to subcarrier block #1508, and data oftransmission data sequence 1 to be transmitted to communication terminalapparatus of user n is allocated to subcarrier block #1509. On the otherhand, data for transmission data sequence 2 transmitted in common tocommunication terminal apparatus of a plurality of users arbitrarilyselected from users 1 to n is allocated to time-multiplexed channels#1502, #1503, #1504, #1505, #1506, #1507, and channels #1502, #1503,#1504, #1505, #1506, #1507 are allocated to subcarriers across eachsubcarrier block #1501, #1508, #1509. Channels #1502, #1503, #1504,#1505, #1506, #1507 are allocated to a plurality of subcarriersdistributed over the whole of the communication frequency band width. Asa result, frequency diversity effects are obtained for data fortransmission data sequence 2. In this event, the frequency diversityeffect is greater for a larger number of allocated subcarriers and agreater spread of subcarrier frequencies.

Next, a description is given of the case where transmission datasequence 1 and transmission data sequence 2 are time-multiplexed. FIG.17 shows the case where the proportion of low-speed data in the numberratio for low-speed data and high-speed data is larger than for FIG. 5,with FIG. 17 showing six low-speed data channels to the three low-speeddata channels of FIG. 5. From FIG. 17 at a predetermined communicationfrequency band width, data of transmission data sequence 1 transmittedto communication terminal apparatus of user 1 is allocated to subcarrierblock #1607, data of transmission data sequence 1 to be transmitted tocommunication terminal apparatus of user 2 is allocated to subcarrierblock #1608, and data of transmission data sequence 1 to be transmittedto communication terminal apparatus of user n is allocated to subcarrierblock #1609. On the other hand, data for transmission data sequence 2transmitted in common to communication terminal apparatus of a pluralityof users arbitrarily selected from users 1 to n is allocated tofrequency-multiplexed channels #1601, #1602, #1603, #1604, #1605, #1606.Channels#1601, #1602, #1603, #1604, #1605, #1606 are allocated to aplurality of subcarriers distributed over the whole of the communicationfrequency band width. As a result, frequency diversity effects areobtained for data for transmission data sequence 2. In this event, thefrequency diversity effect is greater for a larger number of allocatedsubcarriers and a greater spread of subcarrier frequencies.

According to the fifth embodiment, in addition to the effects of thefirst embodiment, the number of high-speed data channels and the numberof low-speed data channels are varied according to various amounts oftraffic. Thus, transmission efficiency can be further improved.

In this fifth embodiment, the number of low-speed data channels and thenumber of high-speed data channels is varied according to the amount oflow-speed data and the amount of high-speed data but this is by no meanslimiting, and it is also possible to vary the number of channels everydata type according to the amount of data every data type, or vary thenumber of channels every movement speed according to the amount of dataevery movement speed for a predetermined range of communication terminalapparatus.

(Sixth Embodiment)

FIG. 18 is a block diagram showing a configuration for a wirelesscommunication apparatus 1700 of a sixth embodiment of the presentinvention.

As shown in FIG. 18, wireless communication apparatus 1700 of this sixthembodiment is wireless communication apparatus 100 of the firstembodiment shown in FIG. 2 with data amount measuring section 1701, usedchannel determination section 1702, and channel configuration controlsection 1703 added. In FIG. 18, portions with the same configuration asfor FIG. 2 are given the same numerals and are not described.

Transmission data processing sections 1704-1 to 1704-n are eachconstituted by control information extraction section 105, demodulatingsection 106, decoding section 107, coding section 109, coding section110, transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113, modulatingsection 114, data amount measuring section 1701, and used channeldetermination section 1702. Transmission data processing sections 1704-1to 1704-n are provided for just the number of users and each of thetransmission data processing sections 1704-1 to 1704-n carries outprocessing on transmission data for transmission to one user.

Data amount measuring section 1701 measures the amount of data fortransmission data and outputs measurement results to used channeldetermination section 1702 and channel configuration control section1703. Data amount measuring section 1701 measures the amount of databefore starting data transmission in order to simplify control. Data isthen transmitted using the same channel until transmission is complete.Data amount measuring section 1701 notifies communication terminalapparatus of measurement results before starting transmission.

Used channel determination section 1702 then compares measurementresults inputted by data amount measuring section 1701 and a thresholdvalue and selects a channel for use. threshold value, used channeldetermination section 1702 selects a data channel allocated tosubcarriers of good reception quality using frequency scheduling andoutputs this to coding section 109 as data for transmission datasequence 1. If the measurement results are less than the thresholdvalue, used channel determination section 1702 selects a data channelallocated to preassigned subcarriers and outputs this to coding section110 as data for transmission data sequence 2.

Channel configuration control section 1703 measures the amount of dataand required transmission speed for user data transmitted to eachcommunication terminal apparatus and calculates a ratio for the numberof low speed data and the number of high speed data (stream numberratio). Channel configuration control section 1703 then sets channelconfiguration in such a manner that a ratio of high-speed data channelsand low-speed data channels is the same as the calculated number ratioand outputs the channel configuration information to channel allocationsection 115 and channel allocation section 116.

Channel allocation section 115 allocates transmission data sequence 1constituted by high-speed data inputted by modulating section 113 tosubcarriers for output to IFFT section 117 based on channelconfiguration information inputted by channel configuration controlsection 1703 and subcarrier information inputted by control section 108.

Channel allocation section 116 allocates transmission data sequence 2constituted by low-speed data inputted by modulating section 114 tosubcarriers to output to IFFT section 117 based on channel configurationinformation inputted by channel configuration control section 1703 andsubcarrier information inputted by control section 108.

In the event that data allocated to subcarriers in this manner isfrequency-multiplexed, as shown in FIG. 16, high-speed data whose amountis greater than or equal to a threshold value is allocated to channel#1501, #1508, #1509, and low-speed data whose amount is less than athreshold value is allocated to channel #1502, #1503, #1504, #1505,#1506, #1507. Further, low-speed data whose amount is greater than orequal to the threshold value is allocated to channels #1501, #1508,#1509, and high-speed data whose amount is less than the threshold valueis allocated to channels #1502, #1503, #1504, #1505, #1506, #1507. Thisis by no means limiting, and low-speed data whose amount is greater thanor equal to the threshold value may also be allocated to channels #1502,#1503, #1504, #1505, #1506, #1507 and high-speed data whose amount isless than the threshold value may be allocated to channels #1501, #1508,#1509.

On the other hand, as shown in FIG. 17, in the case of time-divisionmultiplexing, high-speed data whose amount is greater than or equal tothe threshold value is allocated to channels #1607, #1608, #1609, andlow-speed data whose amount is less than the threshold value isallocated to channels #1601, #1602, #1603, #1604, #1605, #1606. Further,low-speed data whose amount is greater than or equal to the thresholdvalue is allocated to channels #1607, #1608, #1609, and high-speed datawhose amount is less than the threshold value is allocated to channels#1601, #1602, #1603, #1604, #1605, #1606. This is by no means limiting,and low-speed data whose amount is greater than or equal to thethreshold value may also be allocated to channels #1601, #1602, #1603,#1604, #1605, #1606 and high-speed data whose amount is less than thethreshold value may be allocated to channels #1607, #1608, #1609.

According to the sixth embodiment, in addition to the effects of thefirst, second and fifth embodiments, in the event that the amount ofhigh-speed data is large but the total amount of high-speed data issmaller than that of the low-speed data, it is possible to improvetransmission efficiency of high-speed data by allocating high-speed datato subcarriers of superior reception quality, and transmissionefficiency of low-speed data is also improved as a result of increasingthe number of channels for low-speed data. The overall transmissionefficiency can therefore be improved for wireless communicationapparatus by setting an optimum number of channels according to the dataamount of low-speed data and high-speed data.

(Seventh Embodiment)

FIG. 19 is a block diagram showing a configuration for a wirelesscommunication apparatus 1800 of a seventh embodiment of the presentinvention.

As shown in FIG. 19, wireless communication apparatus 1800 of thisseventh embodiment is wireless communication apparatus 100 of the firstembodiment shown in FIG. 2 with data amount measuring section 1801, newdata used channel determination section 1802, and retransmission dataused channel determination section 1803. In FIG. 19, portions with thesame configuration as for FIG. 2 are given the same numerals and are notdescribed.

ontrol information extraction section 105, demodulating section 106,decoding section 107, coding section 109, coding section 110,transmission HARQ (Hybrid Automatic Repeat Request) section 111,transmission HARQ section 112, modulating section 113, modulatingsection 114, data amount measuring section 1801, and new data usedchannel determination section 1802. Transmission data processingsections 1804-1 to 1804-n are provided for just the number of users andeach of the transmission data processing sections 1804-1 to 1804-ncarries out processing on transmission data transmitted to one user.

Data amount measuring section 1801 measures the amount of data fortransmission data and outputs measurement results to new data usedchannel determination section 1802. Data amount measuring section 1801measures the amount of data before starting data transmission in orderto simplify control. Data is then transmitted using the same channeluntil transmission is complete. Data amount measuring section 1801notifies communication terminal apparatus of measurement results beforestarting transmission.

New data used channel determination section 1802 then comparesmeasurement results inputted by data amount measuring section 1801 and athreshold value and selects a channel for use. Namely, if themeasurement results are greater than or equal to the threshold value,new data used channel determination section 1802 selects a data channelallocated to subcarriers of good reception quality using frequencyscheduling and outputs this to coding section 109 as data fortransmission data sequence 1. If the measurement results are less thanthe threshold value, new data used channel determination section 1802selects a data channel allocated to preassigned subcarriers and outputsto coding section 110 as data for transmission data sequence 2.

Retransmission data used channel determination section 1803 determineswhether transmission data inputted by modulating section 113 andmodulating section 114 is new data or retransmitted data. In the case ofnew data, the data is sent as is to channel allocation section 115 andchannel allocation section 116. In the case of retransmitted data, thisdata is outputted only to channel allocation section 116 as data fortransmission data sequence 2 as a result of allocation to preassignedsubcarriers.

Channel allocation section 115 allocates new data inputted byretransmitted data used channel determination section 1803 tosubcarriers based on subcarrier information inputted by control section108 and outputs this to IFFT section 117. Channel allocation section 115allocates the new data to subcarriers of superior reception quality.

Channel allocation section 116 allocates new data or retransmitted datainputted by retransmitted data used channel determination section 1803to subcarriers based on subcarrier information inputted by controlsection 108 and outputs this to IFFT section 117. Channel allocationsection 116 allocates the new data or retransmitted data to preassignedsubcarriers.

Next, a description is given of the operation of wireless communicationapparatus 1800 using FIG. 20. FIG. 20 is a flowchart showing theoperation of wireless communication apparatus 1800.

First, data amount measuring section 1801 measures the amount of data(step ST1901).

Next, new data used channel determination section 1802 compares themeasured amount of new data and a threshold value and determines whetheror not the amount of data for the new data is greater than or equal tothe threshold value (step ST1902).

In the event that the amount of new data is greater than or equal to athreshold value, new data used channel determination section 1802determines allocation of new data to subcarriers of superior receptionquality (step ST1903).

On the other hand, in the event that the amount of new data is less thanthe threshold value, new data used channel determination section 1802determines allocation of new data to preassigned subcarriers (fixedallocation) (step ST1904).

Next, retransmitted data used channel determination section 1803determines whether or not input data is retransmitted data (stepST1905).

In the event that retransmitted data is not inputted, retransmitted dataused channel determination section 1803 outputs the data as is (stepST1906). As a result, at channel allocation section 115 and channelallocation section 116, the new data is allocated to channels determinedat new data used channel determination section 1802.

On the other hand, in the event that retransmitted data is inputted,retransmitted data used channel determination section 1803 determinesallocation of the retransmitted data to preassigned subcarriers (fixedallocation) (step ST1907).

Next, wireless communication apparatus 1800 transmits the new data orretransmitted data allocated to subcarriers (step ST1908). With theexception of data where new data for which the amount of data is greaterthan or equal to a threshold value being allocated to subcarrier blocksand data where the amount of data is less than a threshold value beingallocated to subcarriers determined in advance, the method of allocatingnew data or retransmitted data to each subcarrier is the same as forFIG. 4 and FIG. 5 and is therefore not described.

According to the seventh embodiment, in addition to the effects of thefirst and second embodiments, retransmitted data is always allocated topreassigned subcarriers and a fixed rate capable of decoding subcarriersretransmitted data is allocated to without errors is applied. It istherefore possible to prevent retransmitted data from being subjected toadaptive modulation using an erroneous modulation scheme thus causingtransmission efficiency to deteriorate with repeated retransmissions.Namely, because retransmitted data is transmitted when transmission datafor the previous time was incorrect, in the event that retransmission isrequested, the case that the transmission did not proceed correctlyusing frequency scheduling and adaptive modulation as a result of CQIestimation errors etc. at the time of the previous transmission is to beconsidered, with there being the possibility that errors may occur atthe time of retransmission for the same reasons. The allocation ofpreassigned subcarriers at the time of retransmission is therefore alsoeffective for this with regards to this in preventing falling oftransmission rate due to repeated retransmissions.

According to the seventh embodiment, it is possible to obtain afrequency diversity effect by allocating retransmitted data topreassigned subcarriers spread over the whole of the communicationfrequency band. It is therefore possible to suppress the effects offading fluctuation with respect to retransmitted data to a minimum andprevent deterioration of transmission rate due to repeatedretransmissions.

In the seventh embodiment, retransmitted data is allocated topreassigned subcarriers but this is by no means limiting, and allocationof retransmitted data with a predetermined number or more retransmissionto preassigned subcarriers is also possible.

(Eighth Embodiment)

In this embodiment, in the configuration for the wireless communicationapparatus and wireless terminal apparatus of the first to seventhembodiments, communication terminal apparatus allocated subcarriers byfrequency scheduling only generates CQI's for a number of subcarriersdesignated by an upper layer station apparatus of communication terminalapparatus such as control station apparatus etc., and reports these tobase station apparatus.

According to this embodiment, the amount of control informationtransmitted by frequency-scheduled communication terminal apparatus canbe made extremely small. The transmission rate can then be furtherimproved by making the amount of control information for the whole ofthe communication terminal apparatus communicating with the base stationapparatus small.

In the first to seventh embodiments and other embodiments, just one ofeither frequency multiplexing or time-dividing multiplexing is used butthis is by no means limiting, and a combination of frequencymultiplexing and time multiplexing is possible as a multiplexing methodfor users of a multicarrier transmission method. In this case, in thefirst embodiment to third embodiment, a time slot for transmittingtransmission data sequence 1 that has been subjected to frequencyscheduling and a time slot for transmitting transmission data sequence 2that has not been subjected to frequency scheduling are decided inadvance. The wireless communication apparatus then allocates time slotsto the transmission data according to properties of the transmissiondata sequence and the propagation path environment. As a result of doingthis, it is merely necessary to change time slot allocation whenadaptively changing the respective number of channels and amount of datatransmitted by the respective channels, and straightforward control cantherefore be achieved. Further, data allocated to subcarriers ofsuperior reception quality as a result of frequency scheduling and dataallocated to subcarriers determined in advance is not limited to thedata of the first to seventh embodiments and further embodiment, andapplication is possible to arbitrary data provided frequency schedulingand adaptive modulation results can be obtained.

The wireless communication apparatus of the first to seventh embodimentsand other embodiment may also be applied to base station apparatus.

(Ninth Embodiment)

The wireless communication apparatus of this embodiment is such that amovement speed estimation section for estimating movement speed of acommunicating party from a received signal is provided for theconfiguration of the third embodiment. The subcarrier allocation sectionthen allocates first data transmitted to a communicating party of amovement speed estimated by the movement speed estimation section ofgreater than or equal to a preassigned threshold value to subcarriersselected by scheduling, second data transmitted to a communicating partyof a movement speed estimated by the movement speed estimation sectionof less than the preassigned threshold value to preassigned subcarriers.

In the subcarrier allocation method of this embodiment, a step ofestimating movement speed of a communicating party from a receivedsignal is provided in the method of the third embodiment. First data tobe transmitted to a communicating party of an estimated movement speedof greater than or equal to a predetermined threshold value is thenallocated to subcarriers selected by scheduling, second data to betransmitted to a communicating party of an estimated movement speed ofless than the predetermined threshold value is allocated to preassignedsubcarriers. Therefore, according to this embodiment, for example, datatransmitted to communication terminal apparatus of a large movementspeed is allocated to subcarriers of superior quality by scheduling.This means that deterioration in reception quality due to fadingfluctuation can be kept to a minimum. Further, data to be transmitted tocommunication terminal apparatus of a small movement speed is allocatedto a plurality of subcarriers determined in advance. It is thereforepossible to make signal processing high-speed because scheduling is notnecessary.

(Tenth Embodiment)

With wireless communication apparatus of this embodiment, in theconfiguration of the first embodiment, the subcarrier allocation sectionallocates second data to a plurality of subcarriers at predeterminedfrequency intervals within the communication frequency band width.

Further, with the subcarrier allocation method of this embodiment, inthe first embodiment, second data is allocated to a plurality ofsubcarriers at predetermined frequency intervals within thecommunication frequency band width.

According to this embodiment, second data is allocated spread over aplurality of subcarriers spanning the whole of the communicationfrequency band width. It is therefore possible to demodulate second datawithout error even in cases where a situation where deterioration ofquality due to fading fluctuation etc. continues for a long time byobtaining frequency diversity effect.

(Eleventh Embodiment)

With a wireless communication apparatus of this embodiment, in theconfiguration of the first embodiment, a subcarrier allocation sectionholds a reference table storing modulation scheme informationcorrelating reception quality information and a modulation scheme. Themodulation scheme is then selected for each subcarrier using receptionquality information for the communicating party, and first data isallocated to subcarriers using scheduling in such a manner that therequired transmission rate for each communicating party is satisfiedusing required transmission rate information. Further, with the methodof allocating subcarriers of the present invention, in the method of thefirst embodiment, reception quality information for a communicatingparty is employed, and a modulation scheme is selected for eachsubcarrier by referring to modulation scheme information associating thereception quality information and the modulation scheme. First data isthen allocated to subcarriers by scheduling in such a manner thatrequired transmission rate for each communicating party is satisfiedusing the required transmission rate information.

Therefore, according to this embodiment, straightforward processing forscheduling can be carried out simply by referring to a reference tableand scheduling is performed in such a manner as to satisfy a requiredtransmission rate. It is therefore possible to receive data of superiorquality at each communication terminal apparatus.

Each function block employed in the description of each of theaforementioned embodiments may typically be implemented as an LSIconstituted by an integrated circuit. These may be individual chips orpartially or totally contained on a single chip.

“LSI” is adopted here but this may also be referred to as “IC”, “systemLSI”, “super LSI”, or “ultra LSI” depending on differing extents ofintegration.

Further, the method of circuit integration is not limited to LSI's, andimplementation using dedicated circuitry or general purpose processorsis also possible. After LSI manufacture, utilization of an FPGA (FieldProgrammable Gate Array) or a reconfigurable processor where connectionsand settings of circuit cells within an LSI can be reconfigured is alsopossible.

Further, if integrated circuit technology comes out to replace LSI's asa result of the advancement of semiconductor technology or a derivativeother technology, it is naturally also possible to carry out functionblock integration using this technology. Application in biotechnology isalso possible.

This specification is based on Japanese patent application No.2003-295971, filed on Aug. 20th, 2003, the entire content of which isexpressly incorporated herein by reference.

Industrial Applicability

The wireless communication apparatus and subcarrier allocation method ofthe present invention is capable of improving transmission rate byselecting data to be subjected to frequency scheduling according to datatype, is effective in achieving high-speed signal processing, and isuseful in allocating subcarriers.

The invention claimed is:
 1. A base station apparatus comprising: adeciding section that decides whether to transmit data using a firstsubcarrier block newly allocated to a terminal, or transmit data using asecond subcarrier block persistently allocated to the terminal, thefirst subcarrier block and the second subcarrier block each including aportion of a whole communication band; a frequency scheduling sectionthat, in case that the deciding section decides to transmit the datausing the first subcarrier block, allocates the first subcarrier blockto the terminal; and a transmission section that, in case that thedeciding section decides to transmit the data using the first subcarrierblock, transmits, in an orthogonal frequency division multiplexing(OFDM) system, information representing the first subcarrier blockallocated by the frequency scheduling section to the terminal andtransmits, in the OFDM system, the data to the terminal using the firstsubcarrier block allocated by the frequency scheduling section, andthat, in case that the deciding section decides to transmit the datausing the second subcarrier block, transmits, in the OFDM system, thedata to the terminal using the second subcarrier block persistentlyallocated to the terminal, wherein the deciding section decides betweenusing the first subcarrier block or the second subcarrier block forinitial transmission of the data but, in case the initial transmissionfails and the data is to be retransmitted, the deciding section decidesto retransmit the data using exclusively the second subcarrier block,wherein the portion of the whole communication band included in thesecond subcarrier block is allocated in a distributed manner along afrequency axis, and wherein a fixed modulation and coding scheme (MCS)is applied to retransmit the data using the second subcarrier block. 2.The base station apparatus according to claim 1, wherein a fixedtransmission rate is applied to retransmit the data using the secondsubcarrier block.
 3. The base station apparatus according to claim 1,wherein the deciding section decides between using the first subcarrierblock or the second subcarrier block for initial transmission of thedata to satisfy a transmission rate determined for the terminal.
 4. Thebase station apparatus according to claim 3, wherein the decidingsection adaptively selects an MCS for initial transmission of the datato satisfy the transmission rate determined for the terminal.
 5. Thebase station apparatus according to claim 4, wherein the decidingsection adaptively selects the MCS for initial transmission of the databased on channel quality indicator (CQI) information received from theterminal.
 6. The base station apparatus according to claim 5, whereinthe deciding section refers to a table that correlates the MCS and theCQI information.
 7. The base station apparatus according to claim 1,wherein the portion of the whole communication band included in thefirst subcarrier block is allocated in a localized manner along thefrequency axis.
 8. The base station apparatus according to claim 1,wherein the predetermined MCS is applied to retransmit the dataregardless of channel quality indicator (CQI) information received fromthe terminal.
 9. A terminal comprising: a determining section thatdetermines whether the terminal is newly allocated a first subcarrierblock by a base station apparatus based on control information receivedfrom the base station apparatus, the first subcarrier block including aportion of a whole communication band; and a receiving section thatreceives, in an orthogonal frequency division multiplexing (OFDM)system, the control information, receives, in the OFDM system, datausing the first subcarrier block indicated by information included inthe control information in case that a determination result is positive,and receives, in the OFDM system, the data using a second subcarrierblock that is persistently allocated to the terminal in case that thedetermination result is negative, the second subcarrier block includinga portion of the whole communication band, wherein the determinationresult is positive or negative for the data that is initiallytransmitted but, in case the initial transmission fails and the data isto be retransmitted, the determination result is exclusively negativefor the retransmitted data, wherein the portion of the wholecommunication band included in the second subcarrier block is allocatedin a distributed manner along a frequency axis, and wherein a fixedmodulation and coding scheme (MCS) is applied to the data to beretransmitted.
 10. The terminal according to claim 9, wherein a fixedtransmission rate is applied to the retransmitted data.
 11. The terminalaccording to claim 9, wherein an adaptive modulation and coding scheme(MCS) is applied to the initially-transmitted data.
 12. The terminalaccording to claim 11, wherein the adaptive modulation and coding scheme(MCS) is applied to the initially-transmitted data to satisfy atransmission rate determined for the terminal.
 13. The terminalaccording to claim 11, further comprising a transmission section thattransmits channel quality indicator (CQI) information indicative ofchannel conditions as determined by the terminal to the base station,and the adaptive MCS is applied to the initially-transmitted data basedon the CQI information.
 14. The terminal according to claim 13, furthercomprising a table that correlates the MCS and the CQI information. 15.The terminal according to claim 9, wherein the portion of the wholecommunication band included in the first subcarrier block is allocatedin a localized manner along the frequency axis.
 16. A transmissionmethod comprising: a decision step of deciding whether to transmit datausing a first subcarrier block newly allocated to a terminal or transmitdata using a second subcarrier block persistently allocated to theterminal, the first subcarrier block and the second subcarrier blockeach including a portion of a whole communication band; a frequencyscheduling step of, when the data is decided to be transmitted using thefirst subcarrier block in the decision step, allocating the firstsubcarrier block to the terminal; and a transmission step of, when thedata is decided to be transmitted using the first subcarrier block inthe decision step, transmitting, in an orthogonal frequency divisionmultiplexing (OFDM) system, information representing the firstsubcarrier block allocated in the frequency scheduling step to theterminal and transmitting, in the OFDM system, the data to the terminalusing the first subcarrier block allocated in the frequency schedulingstep, and, when the data is decided to be transmitted using the secondsubcarrier block in the decision step, transmitting, in the OFDM system,the data to the terminal using the second subcarrier block persistentlyallocated to the terminal, wherein the deciding step decides betweenusing the first subcarrier block or the second subcarrier block forinitial transmission of the data but, in case the initial transmissionfails and the data is to be retransmitted, the decision step decides toretransmit the data using exclusively the second subcarrier block,wherein the portion of the whole communication band included in thesecond subcarrier block is allocated in a distributed manner along afrequency axis, and wherein a fixed modulation and coding scheme (MCS)is applied to retransmit the data using the second subcarrier block. 17.A receiving method comprising: determining whether a terminal is newlyallocated a first subcarrier block by a base station apparatus based oncontrol information received from the base station apparatus, the firstsubcarrier block including a portion of a whole communication band; andreceiving, in an orthogonal frequency division multiplexing (OFDM)system, the control information, receiving, in the OFDM system, datausing the first subcarrier block indicated by information included inthe control information in case that a determination result is positive,and receiving, in the OFDM system, the data using a second subcarrierblock that is persistently allocated to the terminal in case that thedetermination result is negative, the second subcarrier block includingpart of the whole communication band, wherein the determination resultis positive or negative for the data that is initially transmitted but,in case the initial transmission fails and the data is to beretransmitted, the determination result is exclusively negative for theretransmitted data, wherein the portion of the whole communication bandincluded in the second subcarrier block is allocated in a distributedmanner along a frequency axis, and wherein a fixed modulation and codingscheme (MCS) is applied to the data to be retransmitted.